ADO.NET Overview

Sample access using Data Reader:

        ' Setup connection

        Dim myConnection As New OleDb.OleDbConnection( _

            "Provider=Microsoft.Jet.OLEDB.4.0;" & _

            "Data Source=C:\Program Files\Microsoft Visual " & _

            "Studio.NET\Common7\Tools\Bin\nwind.Mdb")

         ' Setup command object, specifying SELECT

        ' and connection to use

        Dim myCommand As New OleDb.OleDbCommand( _
          "Select * from Customers", myConnection)

        Dim myReader As OleDb.OleDbDataReader  

        ' Open connection

        myConnection.Open()

        ' Execute and put results into reader

        myReader = myCommand.ExecuteReader

        ' Read through all the records

        Do Until myReader.Read = False

            MessageBox.Show(myReader("CompanyName"))

        Loop

        ' Close reader connection before continuing

        myReader.Close()

        myConnection.Close()

Sample access using Data Adapter:

        ' Setup connection

        Dim myConnection As New OleDb.OleDbConnection( _

            "Provider=Microsoft.Jet.OLEDB.4.0;" & _

            "Data Source=C:\Program Files\Microsoft Visual " & _

            "Studio.NET\Common7\Tools\Bin\nwind.Mdb")

        ' We're just specifying the SELECT here.

        ' If done visually using the Server Explorer,

        ' the INSERT/UPDATE/DELETE + Parameters

        ' collection would be auto-specified for us

        Dim myDataAdapter As New OleDb.OleDbDataAdapter( _
          "Select * from Customers", myConnection)  

        Dim myDataSet As New DataSet()  

        ' Fill DataSet with table, call it 'Customers'

        myDataAdapter.Fill(myDataSet, "Customers")  

        ' Display first CompanyName field of first

        ' row in Customers table

        MessageBox.Show(myDataSet.Tables("Customers").Rows(0)("CompanyName"))  

        ' If we had specified INSERT/UPDATE/DELETE

        ' commands + Parameters collection, we could

        ' also now edit the data, then run something like:

        '    myDataAdapter.Update(myDataSet)  

Sample access using XML:

        Dim myDataSet As New DataSet()

        myDataSet.ReadXml("c:\books.xml")

        ' Books.xml is file bundled with VS.NET,

        ' typically located at:

        ' C:\Program Files\Microsoft.NET\FrameworkSDK

        ' ... \Samples\quickstart\howto\samples\xml

        ' ... \xmldocumentevent\vb\books.xml

         ' Counts the number of book nodes

        MessageBox.Show(myDataSet.Tables("book").Rows.Count)

         ' Retrieves the last name of the first author

        MessageBox.Show(myDataSet.Tables( _
          "author").Rows(0)("last-name"))

         ' Updates the last name

        myDataSet.Tables("author").Rows(0)( _
          "last-name") = "Flandadenham"

         ' Rewrites the XML file

        myDataSet.WriteXml("c:\books.xml")